Why Does A1C Differ Among Races?

In various studies, researchers have found that A1C scores and treatment decisions differ significantly among different ethnic populations – the ratio of people on pump therapy across ethnic groups is extremely disproportionate and, as a U.K. audit report attested, white populations achieve lower average A1C scores. For a while, it was believed that differences in socioeconomic status was the reason behind this, but a recent study published in the journal Pediatrics found that this didn’t explain the disparities in diabetes care among children under 18 years old.

Using the T1D Exchange Clinic Registry, the research team collected a year’s worth of information from about 10,700 kids, 214 of which were Hispanic or black children from high-income backgrounds. Lead study author Dr. Steven Willi says that his team adjusted for modes of socioeconomic status like level of parental education, finances, and private versus public insurance plans and still didn’t have a definitive answer for the disparity.

“I was prepared to come to the conclusion that it would be socioeconomic status, so I was a bit surprised [by the results],” he says.

According to a Reuters article, black children, who comprised 7% of the total survey pool, had average A1c scores of 9.6%, significantly higher than the Hispanic (8.7%) and non-Hispanic white (8.4%) children that were also studied.

If social and economic status aren’t relevant, it would be fair to suggest that doctors simply need to get more children of color on CGM and pump therapy. It’s not that simple, says Dr. Elizabeth Littlejohn, an associate professor of pediatrics at the University of Chicago, who wasn’t involved in the study.

“Different ethnic groups have different ways they look at diabetes,” Dr. Littlejohn says. “I think it’s multifactorial, [including] cultural differences, family history with the disease…it’s a little bit of everything.”

Dr. Rochelle Naylor, who serves as assistant professor in adult and pediatric endocrinology, diabetes, and metabolism at the University of Chicago (and who also wasn’t involved with the study), agrees that there are a few factors at play.

“There are a number of healthcare and cultural factors that are working in unison to produce these results,” she says.

Dr. Naylor suspects that provider interactions may vary with minority populations. From her own experience, she has recognized differences in the treatment of pain among black sickle cell patients versus white patients with irritable bowel syndrome. Furthermore, she says pump therapy is not offered as often to minority populations. And while she and Dr. Littlejohn say they make sure all their patients are aware of continuous glucose monitors as a treatment option, it appears the medical community might have unknowingly crafted a concept of the “ideal” pump candidate.

“I have come from the bias that there is an ideal pump candidate,” Dr. Willi said. “If someone’s A1C was too high, then [I thought] they hadn’t ‘earned’ a pump. But this is no longer relevant—it needs to be about educating everyone.”

Dr. Littlejohn also believes there could be biological differences influencing the disparities, It’s been shown in previous research that glycated hemoglobin is higher in black individuals, Dr. Naylor points out. So the question then becomes, should black children even be striving for lower A1C scores, or do we need to say, at baseline, a non-diabetic African-American will run a higher A1C than a non-diabetic Caucasian? To answer this, there needs to be more research that examines genetic differences in minority populations.

The Diabetes Center for Children in Philadelphia is a contributing center for a new study that is seeking to address this issue. While Dr. Willi can’t give details on the research gathered so far, he projects the findings will be published in the next six months and likely presented at the American Diabetes Association meetings next year.

It appears that there are various components that need to be taken into account when addressing this disparity. If there is subliminal bias within the medical community, Dr. Naylor says it’s important to become aware of these biases and correct them. And if biology is a factor, expected A1C scores need to be redefined to something more universal rather than just being suitable for a majority population. After all, diabetes is a vastly complicated disease, so maybe the way we define it shouldn’t be so straightforward either. For any of this to happen, however, it’s important to advance the conversation on this issue.

“This issue gets less attention because it’s affecting a population that doesn’t influence policy,” Dr. Naylor states. “But if we don’t capture a diverse population from the outset, then we’re going to have difficulties when we try to apply our knowledge.”

Travis served as a staff writer for Insulin Nation and Type 2 Nation in 2015. Previously, he was a staff writer for Insight, a high school newspaper, as well as a copywriter for The Emersonian, Emerson's yearbook.

| July 15th 2014

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